# Validation & Deployment

## Validate Locally, Deploy Once

The single biggest time sink across projects is "deploy first, validate later." Real-world stats from a 9-milestone infrastructure project showed 50-60% of commits were fixes that could have been caught locally.

**Always validate before pushing:**
- `helm template` for Helm chart values
- `kustomize build` (or `kubectl kustomize`) for Kustomize apps
- `kubectl apply --dry-run=server` for K8s naming/schema issues
- `docker run <app> validate-configuration` for apps that support it (Authelia, Homepage, etc.)
- `docker inspect` for unfamiliar container images before writing init containers
- Lint/typecheck/test for application code

**Batch fixes locally, push once.** Each push-sync-crash-fix cycle wastes minutes and clutters Git history.

## Test the Full Chain Immediately

After wiring up any new service or endpoint, test end-to-end from the user's perspective right away. Don't assume intermediate steps working means the whole chain works.

- `curl --resolve domain:443:<ip> https://domain` to test bypassing DNS/proxy layers
- Test from the actual consumer (not same-namespace test pods for network policies)
- Test DNS resolution after deploying FQDN-based policies

## Pre-Flight Checks

Before starting a deploy or automation phase:
- Verify SSH keys are loaded (`ssh -T git@<host>`)
- Confirm environment variables and credentials are available
- Check that the target environment is in the expected state
- Verify DNS records resolve as expected

## Scripts That Change Config Must Self-Verify

After updating and restarting a service, the script should test that the change actually took effect (e.g., curl an API endpoint, check a config value). A "success" message without verification hides failures.